A brief overview of a turbo system 'components' in the context of an IDI

[Heide264]

Good Evening.

I've decided to do an 'armchair warrior writeup' for discussion and reference. While my past 'armchair warrior writeups' on other forums have required a nice day, plenty of good beer, and several cigars... some crappy red wine, my college graphing calculator, and a book will have to do for now. For some reason, all of my nice days seem to go into a large one ton pickup that is still keeping my driveway from blowing away.

This thread spawned out of this thread here: http://www.oilburners.net/forums/showthread.php?71879-turbos-wastegates-and-blow-off-valves
There is some great information in that thread, from several different view points. I don't intend to discredit any of those view points in here, I just would like to 'tie it all together' as best as I can and add on what may be useful.

I learned most of what I know about cars after getting a 2011 Subaru STi years ago. Before that, I didn't even know how to do an oil change. The more I looked around, the more I realized a lot of people had no idea what the heck they were doing. I got a few books, started fixing my own tune, and dumping way more money into it than I should have. Long story short, I learned a LOT in a short period of time. Some of it is applicable to giant non-EFI diesel trucks... some not. However, I figure you guys deal with my stupid questions regarding power steering lines and vacuum pumps, so I may as well share what I can.

It's a long thread. If you don't like reading, sorry. If you do like reading, I'd love some discussion on the material. Hopefully this benefits the community and is a nice reference for those in the future. I'll try to put the important stuff in bold, regardless.

I'm going to cover an overview of some various terms and concepts in here. I'll also reserve a Q&A posting or two to sum up some of the discussion, if any follows.

Turbocharger:
A device that drives more air into an engine. In an engine, power is created by burning fuel in the presence of air. If you have no air, you have no combustion. Turbochargers primarily use the heat from the engines exhaust to spin a turbine wheel, which is connected via a shaft to a compressor wheel. The compressor spins and compresses air in the intake manifold. While the power in either a gas/diesel engine is dependent on fuel burning, both engine types require some form of air to allow that fuel to burn. More air mass => more fuel can be burnt => more power.

It is important to note that a turbocharger has 'specs'. There is no 'one turbocharger to rule them all'. Every compressor/turbine/housing combination is unique. They are sized to be efficient within certain airflow (lbs/min) at certain pressure ratios (psi/psi... it has no unit). If you go outside that ratio, the turbo is less efficient at compressing air and will heat the air up - quickly. If we step back and look, the goal of a turbo is to get more air into our engine - thats a mass... not a volume or a pressure. The air mass your engine can 'injest' at a given time depends on a few things - the time and space the air has to enter the combustion chamber (re: cam profile, valves), the pressure differential within the chamber to the intake manifold ('boost' pressure), and the density of the air entering the chamber. It's important to understand that your engine cares about air MASS when you are talking about power gains. For example, one cylinder of air at 15psi and 100F contains less mass than the same cylinder at 15psi at 120F which contains less mass than the same cylinder at 17psi but 300F (I think... I'm not crunching the numbers now... its the idea that's important here, haha).

The bottom line is that as a turbocharger moves out of its efficiency range, it turns into a much less useful hair dryer sorta thing. There are many situations where increasing your 'boost pressure' will actually HURT power levels due to the high temperatures involved. As the temperatures climb, the air in the intake manifold is less dense (even if under higher pressure) and the bottom line is that the engine will injest less air MASS even under the higher pressure. I can't really think of a good analogy for this.

The good news is that diesel trucks run in a relatively small operating range! If the turbo is selected properly, you should be able to stay in good efficiency ranges most of the time . Gassers... yeah... sorry guys. Those 8k rev bands have their drawbacks .


The Wastegate:
Simply a valve that allows air around your turbo's turbine. This can be built into the turbo (Internal WG - IWG) or otherwise connected to the exhaust manifold (External - EWG). The basic idea is that you can route gas around the turbine instead of through it. This allows you to not build more boost. I worded it like that for a reason. As discussed above, you may not always want more boost pressure... however... the turbo may keep cranking it out whether you want it or not depending on your turbo, engine selection, and several other factors. A good example of why you would want a wastegate is if you wanted a flatter power band for a wider RPM range, or a much higher torque 'peak' and maybe not as much power at redline (pending engine). You could select a turbo that is more efficient at a lower air flow and higher drivepressure... and then allow the wastegate to keep the turbo within its sweet spot as you approach redline.

A wastegate can be a useful safety function for a turbo as well. In some turbo systems, it is possible to drive the turbo faster than it is spec'd to. A properly sized wastegate will help to prevent this.


Boost Controller:
A wastegate is basically a spring tensioned valve that opens whenever it sees a pressure above a certain amount. I do not know what the spring tension is - I'm assuming somewhere around 10psi. In some applications, a separate device - a boost controller - either an adjustable manual one or an electronic solenoid based one - is plumbed in the middle to 'block' the wastegate from seeing the full manifold pressure. This allows you to use different boost pressures than what your wastegate spring is set at. In a gasser, an electronic boost controller mated up to a properly tuned computer is a powerful asset. If you see the acronyms MBC (manual boost controller) or EBCS (electronic boost control solenoid) tossed around, they aren't applicable to our trucks in a factory configuration. A MBC is, in my opinion, not a bad investment if anybody is looking to play around with different boost levels on a wastegated turbo. It's kinda important to note that if you don't have a wastegate... there is nothing for a separate boost controller to control.


Blow off Valves:
So as a disclaimer, I hate BOVs. They annoy the crap out of me, personally. That being said, in terms of an IDI, they are 'not applicable'. A Blow off valve (BOV) or bypass valve (BPV) allows a pressurized intake track (intercooler & plumbing) to 'vent' due to the now closed throttle blade which is sealing shut the intended air path. Instead of applying pressure on the compressor wheel/housing, the air is either vented to the atmosphere or recirculated back to the intake (pre-compressor). In an IDI, we have no throttle blade... and hence no pressure 'backup' in the intake track. In most diesels (some newer diesels have throttle blades for egr/exhaust gas recirculation), the main thing you need to realize is that a BOV is NOT a wastegate. A BOV vents the intake track between the compressor wheel and the throttle. A Wastegate vents the exhaust manifold to prevent the turbine (and hence the compressor) from spinning faster.


Some closing thoughts:
In my opinion, the merit of a wastegated turbo is a pretty hot topic for an IDI. It appears that the big limiting factor in IDI world is the intake pressure. The head gaskets just seem to be the limiting factor if you can get the fuel in the engine. If you are limited by drive pressure, it should be an important priority to make sure you are really giving the engine all the air mass you can give it at a given pressure. I think the best efforts would be spent on a turbo that spools before you are through most of your power band (e.g. smaller than 'ideal') but has the proper supporting mods to keep the air as dense as possible as the turbo leaves its prime - a proper sized intercooler and **** injection, for example. I'm not too familiar with tuning injection pumps, but if the fuel supply can be made to match a boost curve a bit better, I think there is a lot of potential out there for a nice fun truck that is extremely reliable.

I'll reserve the next post for any Q&A that comes up by myself or other people who know more than myself, and I'll reserve a post after that for some numbers that I will run at a later day.

EDIT: I forgot to give credit as needed. A lot of my turbo specific knowledge comes from "Turbo: Real World High-Performance Turbocharger Systems" by Jay K. Miller. It's a great book, and is actually a pretty quick read. If you guys actually read through this thread, I can't recommend enough to just go buy it on amazon for ~$10. A book is so much more coherent than an internet forum, especially one with my rambling in it.

 

[Heide264]

Q & A:

1.) What is the difference between a BOV (Blow off valve) and BPV (Bypass Valve)?

Depending on the context and the location used, interchanging the terms will get you a generic five minute lecture on their differences and differentiating them will get you a five minute lecture on them being identical.

Many gasoline cars use a Mass Air-Flow (MAF) sensor to determine how much air has entered the engine. It adds in several (depending on the EFI controller - normally the cars ECU) compensations, looks at a fueling table, and injects the corresponding amount of fuel. On the flip side, some cars use a Manifold Air Pressure (MAP) Sensor along with more critical compensations to determine how much fuel to inject. While MAF cars are generally easier to tune (and more forgiving of further modifications, sometimes), MAF fueling normally has a few draw backs as cars increase in power, especially if a 'large' cam is used on a smaller engine. Converting between a MAF based control system and MAP based can be tedious and normally requires a different controller or aftermarket ECU.

All said and done, when dealing with a blow off valve that is releasing air to the atmosphere, that air has already been 'metered' in a MAF based system. For all the air that is released to the atmosphere, the ECU assumes that it still needs to inject fuel for that air. The severity of the issue tends to be a bit over played, but it will cause you to run a bit rich in between aggressive shifts. In a MAP based car, that issue is eliminated.​

If differentiated, a BOV releases the pressurized air to the atmosphere. A BPV 'recirculates' the pressurized air back to the intake after the MAF sensor - so the metered air stays internal to the system. There are hybrid versions that release 50% of the air to atmosphere and recirculate 50% of the air.

Along these lines, while it may not be an issue for most, there are legality issues with running a VTA (vent to atmosphere) type device. I don't fully understand why it would be an emissions issue (as it's before fuel injection), but it is a worthy disclaimer. I would assume if you are recirculating any exhaust gases, that would make sense.
​

2.) What is turbo surge?

I'll defer to garrett for this one: http://www.turbobygarrett.com/turbobygarrett/surge_line

In gasoline cars, surge is a lot more common due to the frequent closing and opening of the throttle blade. Most gasoline cars use a BOV/BPV to help prevent this.

Even though it does not make sense to use a BOV/BPV on a diesel, turbo diesels do in fact experience turbo surge. As to a solution, if you have a pretty penny, go for a ported compressor shroud. Otherwise, try to avoid rapid transients that may revert or stall the gas flow in the intake track quickly.
​

3.) Why do I have boost pressure at idle in my turbo diesel and not in my rice burner?

I'm not quite sure about this one. BDCarrillo pointed out below that the exhaust gas at idle for a large diesel is enough to keep the turbine spinning.

I believe it also has to deal with the fact that that diesels have better emissions under boost where as gas cars have generally worse emissions under boost... and the turbo is sized accordingly.

Any more input on this one?
​

 

[Heide264]

So while bearing with me (I'm not very knowledgeable about these 6.9/7.3 engines), lets walk through what to look for in a compressor. Compressor wheels are a bit easier than turbines to do theoretically, as normally turbo manufacturers give notably better documentation regarding their compressors over their turbines. Note that I don't have this stuff memorized, I am not perfect, and I am following that 'turbo' book to go through this at the moment. Most of my other sources are intended for gassers, so you get Jay Miller's version instead of Greg Banishes version, ha.

First note: Airflow is going to be in mass/minute (lbs/min, normally). In N/A engines you'll normally see CFM (which is a volume measurement, not mass). Volume doesn't take into account density - mass does.

Assumptions:
-Max RPM is 3000RPM
-80% VE (optimistic, I have a feeling)
-14.7psi ambient pressure
-78% compressor efficiency at RPM

Let's aim for 15psi at 'max flow' for now on a 7.3L engine. I didn't pick this for any real good reason at all. It's just for sake of example. While we don't care too much about pressure (directly) when it comes to horsepower, it's a good starting point because it is normally your limiting factor. From what I've found, I'd pick a maximum pressure that gives you some safety margin with the head gaskets. Now, let's work towards finding our mass flow. Since engines are sized in terms of volume, we have some math to do.

At 7.3L, you have 7,300cc. To go from cc(cubic centimeter) to cubic inches, divide by 16.387. That gives you 445.475ci (cubic inches).


Now that you have the engines volume in a nice format, let's find the actual displacement volume as if it was naturally aspirated:
CFM = Volume(ci) * Max RPM * 1/2 (four cycle takes two revolutions) / 1,728 (unit conversion from ci to cubic feet)
CMF = (445.475) * (3000) * 0.5 / 1,728 = 386.697 CFM

Let's assume our engine is only 80% efficient. 386.697 CMF * 0.80 = 309.358 CFM


Okay - now to the 'boosted' part. To determine our 'boosted' CFM, we need to do a few things. First, we need to determine an absolute pressure ratio that we can use for a few important graphs.

At X psi of 'boost' (gauge pressure), we have an absolute pressure ratio of (X + 14.7)/14.7.
(15 + 14.7)/14.7 = 2.02

We take that pressure ratio and use a black magic chart that takes into account compressor efficiency to determine a 'density ratio'. I don't have a copy of these graphs available. They are Density ratio vs Boost (PSI) Pressure Ratio. I am sure you can find one with some googling. Note that this is where things start to differ for intercooled and non-intercooled applications. I am going to assume a compressor efficiency of 78% at max RPM.
With a PR (Pressure ratio) of 2.02 and a compressor efficiency of 78%, I am reading a density ratio (DR) of about 1.58 without intercooling and a DR of 1.75 with intercooling.

CFM with turbo and no I/C = N/A CFM * DR = (309.358) * (1.58) = 488.786 CFM
CFM with turbo and I/C = N/A CFM * DR = (309.358) * (1.75) = 541.377 CFM

Now since we are dealing with choosing a turbo, we go back to a mass flow in place of our volume (we want lbs/min, not CFM). Standard air density is 0.069 (lbs mass/cubic ft of air).
Mass flow = CFM * 0.069
Non-I/C Mass flow = 488.786 * 0.069 = 33.7 lbs/min
I/C Mass flow = 541.377 * 0.069 = 37.4 lbs/min


Okay. Hard part is done. I'll find some compressor graphs and finish this up in the near future. My beer glass is empty and I'm worried I'll lose this post somehow.

EDIT: Hey guys. I didn't forget about this thread. I'll get some more time to finish it up sometime soon. I was making up a spreadsheet, but got stuck calculating the density ratio. It looks like I'll have to make some pretty far out there assumptions or do some reading on typical pre/post compressor temps for these trucks. Sorry it's taking so long!

 

[BDCarrillo]

Nice nice, I learned my turbo stuff on an SRT4. Can't say I agree that ball bearing turbos are "Ok" without a BOV on gassers. Reversion, surge, and and abnormal bearing loads will exist regardless of the type of bearing in the CHRA in the absence of a BOV (or surge valve, in some circles).


Another key difference between gassers and diesels would be the much higher volume of exhaust at idle. My 6.4 PSD would generate about 1 psi of boost at idle.


A wastegate can also prevent an over-rev of the turbocharger itself, in a properly designed max efficiency system.

 

[Heide264]

Nice nice, I learned my turbo stuff on an SRT4. Can't say I agree that ball bearing turbos are "Ok" without a BOV on gassers. Reversion, surge, and and abnormal bearing loads will exist regardless of the type of bearing in the CHRA in the absence of a BOV (or surge valve, in some circles).

Ya know, I thought that this book in front of me was the source that told me that. I can't find it in here. It does advise using a bypass valve over a blow off valve unless in a drag racing build, but I don't see where the comments regarding excluding one all together. I'll edit the post and can always add a note in there if I find the source eventually.

 

[BDCarrillo]

Ya know, I thought that this book in front of me was the source that told me that. I can't find it in here. It does advise using a bypass valve over a blow off valve unless in a drag racing build, but I don't see where the comments regarding excluding one all together. I'll edit the post and can always add a note in there if I find the source eventually.

A bypass valve is mostly required on MAF cars where the air has already been measured and is reintroduced upstream of the MAF. Some MAF applications work just fine venting to atmosphere, based on how they go from a closed to open loop. A tad rich after a hard run does wonders for cooling.

MAP (or carb'd for that matter) won't give a darn on venting to atmosphere.

Do keep in mind that surge can occur in diesels with a drastic change in RPM. Listen to just about any pulling truck. The turbo is outputting a given mass of air, and as the RPMs drop from WOT to idle, the mass flowing through the engine drops significantly. The inertia of the turbocharger wheel is sufficient to keep producing an "excess" of boost for a couple seconds.


For the sake of debate I would claim that a non-wastegated turbo is less efficient than a properly sized wastegated turbo.

 

[BrandonMag]

I appreciate the comments. I will be purchasing the "Turbo" book by Jay Miller shortly.
It will probably make me rethink the forced induction setup on my F350.

 

[jay22day]

Im not trying to bust your balls but it seems to me that you just read a book and this thread is you trying to summarized it.... Not all of your info is correct nor properly explaineD. BEFORE 2011 YOU DIDNT EVEN KNOW HOW TO CHANGE OIL IN A CAR AND NOW YOUR ON HERE TRYING TO GIVE FULL BLOW RIGHT UPS ON COMPLEX TOPICS GUYS LIKE MYSELF HAVE SPENT 10 PLUS YEARS RESEARCHING AND TESTING????

As you know this has all already been covered in the http://www.oilburners.net/forums/sho...low-off-valves so why would you make a new one with inaccurate info?

I already posted a shorter more explanatory right up thats fully accurate in http://www.oilburners.net/forums/sho...low-off-valves


Your information is not fully correct and if you do not more than fully understand what your talking about you should really be reading instead of trying to do full blown write ups informing people with information that is not fully accurate. This forum is full of very knowledgeable people who more than understand this stuff so leave it to them to teach. Feeding miss information to someone trying to learn isn't helping anyone. It takes more than a book and owning a turbo car for a couple years to become a guru on such topics.

Removed informative corrections becuase of threats of banning

seriously i should not have to spend 45 minutes writing an "edit page" correcting your miss information. Yesterday you were involved in the thread you linked here where i posted everything that i just had to correct you on here.

Did you not even read my informative posted in the other thread? and then start a new thread with inaccurate information?

 

[jay22day]

If you have to reread material to post a thread like this you shouldn't be doing write ups, everything i corrected you on is basic knowledge already earned through experience, i need not go back to check references on, this is what happens when you completely know and udnerstand what your talking about.

for the sake of a fellow member not getting confused by your inaccuracies you or maybe a moderator should jsut remove the thread so upon search members find http://www.oilburners.net/forums/showthread.php?71879-turbos-wastegates-and-blow-off-valves witch has correct very use-full information rather than this thread that is misleading.

Again im not here to insult you im posting this to protect other members from getting information that is not correct; that could result in them damaging a turbo, engine or worse.

edit: prior to me posting the corrections of the misinformation, there has already beeen 168 people that read this thread that now could have corrupted/incorrect information.

 

[Heide264]

Nice nice, I learned my turbo stuff on an SRT4. Can't say I agree that ball bearing turbos are "Ok" without a BOV on gassers. Reversion, surge, and and abnormal bearing loads will exist regardless of the type of bearing in the CHRA in the absence of a BOV (or surge valve, in some circles).


Another key difference between gassers and diesels would be the much higher volume of exhaust at idle. My 6.4 PSD would generate about 1 psi of boost at idle.


A wastegate can also prevent an over-rev of the turbocharger itself, in a properly designed max efficiency system.

I'm not doubting that the loads exist regardless of bearing type, just that ball bearings are much more 'friendly' to loads in those directions, as opposed to a traditional journal bearing. I'll take it off. While my opinions on the matter may differ a bit, I'm not looking to start a debate about this here. I just wanted an overview to try to sum up some of the questions.

Interesting on the manifold pressure at idle. I'll add it in. I'm surprised, because you'd think the exhaust heat would be pretty low at idle for a diesel.

I've never heard of the WG preventing an over-rev of the turbocharger itself. I guess it's possible, I just never think too much about over-revving the turbo.

A bypass valve is mostly required on MAF cars where the air has already been measured and is reintroduced upstream of the MAF. Some MAF applications work just fine venting to atmosphere, based on how they go from a closed to open loop. A tad rich after a hard run does wonders for cooling.

MAP (or carb'd for that matter) won't give a darn on venting to atmosphere.

Do keep in mind that surge can occur in diesels with a drastic change in RPM. Listen to just about any pulling truck. The turbo is outputting a given mass of air, and as the RPMs drop from WOT to idle, the mass flowing through the engine drops significantly. The inertia of the turbocharger wheel is sufficient to keep producing an "excess" of boost for a couple seconds.


For the sake of debate I would claim that a non-wastegated turbo is less efficient than a properly sized wastegated turbo.

Agreed on that MAF vs MAP debate. I actually deleted a small paragraph on that ordeal. I tend to type walls of text and just took it out.

So yeah, surge can definitely occur, but strictly in the sense that you ended up way over to the left of the compressor map. It's not something that you'd fix with a BOV/BPV in these cases. I'll add a note in above about it.

I appreciate the comments. I will be purchasing the "Turbo" book by Jay Miller shortly.
It will probably make me rethink the forced induction setup on my F350.

I wouldn't change your opinion too quickly. While it's good to understand a lot of the stuff behind it, going with a known/popular setup is a great starting point. Good luck. There are a few others I'd recommend as well, but the diesel specific information I've found has been pretty poor. If you get through it, shoot me a PM and I can suggest a few others based off what you want.

Im not trying to bust your balls but it seems to me that you just read a book and this thread is you trying to summarized it.... Not all of your info is correct nor properly explaineD.

Man... Simmer down a bit and lay off the caps-lock key. I just wanted to sum this info up in a little more coherent of a post . Lay off the caps lock and we can discuss some of the points, if you want.

I don't really need/want/care to cite references for myself, but I like to think that I am a pretty well respected person out there on the all powerful interwebs. I give that humble disclaimer for a reason. If I don't know something, I go pick up several books and learn it. In the grand scheme of things a BOV, a wastegate, and a simple turbo setup should not take you 10+ years of research to describe at a high level.

If you don't like the thread, ignore it. If you disagree with the information in it, be constructive.

I'll quote your message and comment on the technical portions in a bit.

 

[Heide264]

YOU CAN ABSOLUTLEY NOT RUNN A GASER WITHOUT A BOV. The fact that you thought this was possible goes to show how little you know about this.

You can. People have. Perrin has ran their time attack car without one for years, for example. They didn't include one on certain front mount kits.

No, they did not run a BPV, either. Just let the system do it's thing.

YOU SEEM TO THINK THAT BOV AND "BPV" ARE DIFFERENT? THEY ARE THE SAME THING you can recirculate or blow off to the atmosphere

It's semantics. No big deal. Traditionally a BOV releases to the atmosphere. A BPV bypasses the air back to the intake. I am aware there are BOVs that also recirculate partially or fully. I didn't think it was applicable to the discussion at the time, so I didn't elaborate.

YOUR INFORMATION ON HOW A BLOW OF VALVE WORKS IS INCORRECT IT DOES NOT BYPASS THE THROTTLE PLATE, IF IT DID THIS THE ENGINE WOULD NEVER REV DOWN.

BLOW OFF VALVE DOES NOT VENT THE INTAKE PRE ENGINE IT VENTS THE INTERCOOLER PIPING PRE INTAKE (PRE THROTTLE PLATE)

Fair enough. I made a slip up. The BOV will vent the I/C piping and the intake manifold. The throttle is not bypassed - I should have said the compressor wheel is bypassed.

WHAT DO YOU EVEN MEAN BY OUR MANIFOLDS ARE THE BOOST CONTROLLERS??? WHAT IS THAT SUPOSE TO MEAN? HOW? WHERE DO YOU GET THIS INFORMATION FROM? I DONT EVEN UNDERSTAND THE MANIFOLD YOUR REFERING TO...INTAKE MANIFOLD? EXHAUST MANIFOLD?

THE BOOST CONTROLER ON OUR TRUCKS IS THE WASTEGATE IF IT EVEN HAS ONE AND THE SPRING IS WITHIN THE GATE. MANUAL VACCUM CONTROLLERS CAN BE ATTATCHED TO THE GATES TO MODIFY THERE OPENING PRESSURE BBBBBUUUUUTTTTT THE PROPER WAY TO DO THIS IS TO REPLACE THE SPRING WITH A HIGHER PRESSURE SPRING

I never said your manifolds are boost controllers. If I did, my mistake. I'll go correct it if so. I was just clarifying that our trucks have no 'boost controller'. I respectfully disagree that the correct way to alter boost is to raise the spring in the wastegate. Using a lower spring pressure allows (if applicable) a boost controller to modulate the boost pressure over a much wider range. I think it's hard to argue with the fact a manual boost controller is easier to adjust than pulling the wastegate actuator apart.

GATED TURBOS Heide264 SAID: "A good example of why you would want a wastegate is if you wanted a flatter power band for a wider RPM range, or a much higher torque 'peak' and maybe not as much power at redline (pending engine)."

WASTEGATED TURBOS: THE INTENT IS NOT "FLATTER POWER BANDS" THE PURPOSE OF A WASTEGATED DIESEL TURBO IS TO HAVE A SMALLER EXHAUST HOUSING THAT WILL ALLOW FOR FASTER SPOOL BECAUSE OF BETTER PRE TURBO EXHAUST PRESSURE

PURPOSE OF GATED TURBO IS SMALLER EXHAUST HOUSING RESULTING IN FASTER SPOOL AND MORE EFFICIENT PEAK POWER. "NOT AS MUCH POWER AT REDLINE" IS INCORRECT.

WHY???? BECUASE THE GATE IS RESPONSIBLE FOR KEEPING CONSTANT HIGHER PRESSURE PRE TURBO, NON GATED HAS LARGE EXHAUST HOUSING RESULTING IN LOWER PRE TURBO PRESSURE AND SLOWER SPOOL TIMES.

Maybe this is due to the typical applications of gated and non-gated turbos you have seen. In general, a wastegated turbo can be used to do whatever the heck you want in the exact same context a non wastegated turbo can be sized to do whatever the heck you want. Depending on the application, it may or may not be worth using a wastegate in the system.

A wastegate has no direct impact on the exhaust housing of the turbo. It's simply something that can be 'added on'.

 

[jay22day]

Lol if they are so simple why cant you even explain them correctly? If so simple then why isn't your information correct or coherent?

Your not summing it up or making it coherent when the other thread has correct information and with-in your "summing it up" you post things that are wrong

the caps is to show the corrections of your miss information and that's all. Its large to draw attention from people being miss informed by your thread.

I need not "simmer down" for im not all "riled up" my feathers my be a little ruffled from loosing my morning to trying to correct your mistakes but i take that on the chin for the sake of preventing people from being miss informed.

 

[jay22day]

You dont even knwo what you typed........

Heide264


Boost Controller:
"A wastegate is basically a spring tensioned valve that opens whenever it sees a pressure above a certain amount. In IDI implementations, this is the manifold. I do not know what the spring tension is - I'm assuming somewhere around 10psi. "

Heide264

"I never said you manifolds are boost controllers. If I did, my mistake. I'll go correct it if so. I was just clarifying that our trucks have no 'boost controller'. "

---------they do have boost controlers, the gate is the boost controller, its the spring in the gate that controls the boost pressure (exhaust gate opening pressure)


Heide264

Fair enough. I made a slip up. The BOV will vent the I/C piping and the intake manifold. The throttle is not bypassed - I should have said the compressor wheel is bypassed.

------no once again it wont vent the intake manifold, once again you dont knwo what your talking about. and you mean compressor housing not compressor wheel. terminology is important if your attempting to teach and your not in a knowledgeable enough position to be teaching anyone.

Heide264

I respectfully disagree that the correct way to alter boost is to raise the spring in the wastegate. Using a lower spring pressure allows (if applicable) a boost controller to modulate the boost pressure over a much wider range. I think it's hard to argue with the fact a manual boost controller is easier to adjust than pulling the wastegate actuator apart.

-----my argument is not that MBC are not as easy, the best way to do it is have a gate that you can change the spring, MBC can fail or block up and alow overspool, less things to go wrong if you just have a gate w. a replaceable spring. Pulling a waste gate is one clip and 2 screws................

 

[sjwelds]

my feathers my be a little ruffled from loosing my morning to trying to correct your mistakes

It's your keyboard. No one was standing over you to "correct" him. If you don't want to "waste your time" then don't.

 

[jay22day]

Heide264

"A wastegate has no direct impact on the exhaust housing of the turbo. It's simply something that can be 'added on'. "

------------Absolutely incorrect. This is the most important info when talking about gated and no gated turbos for these trucks.

When designed for these trucks a gated turbo comes with a smaller exhaust housing witch is why the gate is added, its a performance advancement in turbocharging.

This is the most important difference and aspects of these system and the fact that you dont know or under stand how these systems are designed or why goes to show that you jsut need to delete this thread.

You sir think you know much more than you do, sorry to be the one that has to inform you of that but you need to stop type and start reading because you have much to learn.

Stop miss informing people.



You said your an "engineer" in the other thread? this can not be the truth, at least not an automotive or mechanical engineer....